The present invention is generally directed to systems and methods for intravenous (“IV”) delivery, by which fluids can be administered directly to a patient. More particularly, the present invention is directed systems and methods for monitoring and/or managing the flow of a liquid to a patient in the context of a gravity-fed intravenous delivery system. An intravenous delivery system according to the invention is used broadly herein to describe components used to deliver the fluid to the patient, for use in arterial, intravenous, intravascular, peritoneal, and/or non-vascular administration of fluid. Of course, one of skill in the art may use an intravenous delivery system to administer fluids to other locations within a patient's body.
One common method of administering fluids into a patient's blood flow is through an intravenous delivery system. In many common implementations, an intravenous delivery system may include a liquid source such as a liquid bag, a drip unit with a drip chamber used to moderate the flow rate of fluid from the liquid bag, tubing for providing a connection between the liquid bag and the patient, and an intravenous access unit, such as a catheter that may be positioned intravenously in a patient. An intravenous delivery system may also include a Y-connector that allows for the piggybacking of intravenous delivery systems and for the administration of medicine from a syringe into the tubing of the intravenous delivery system.
Such intravenous delivery systems often function via “gravity feed.” In a gravity feed system, the liquid source may be elevated above the patient, so that a “head” or pressure differential exists between the liquid in the liquid source, and the location at which the liquid is delivered to the patient. The pressure differential may enable pumps or other fluid transfer mechanisms to be eliminated, thereby reducing the cost and bulk of the intravenous delivery system.
Unfortunately, many such intravenous delivery systems have difficulties maintaining a constant flow of the liquid to the patient. The level of the liquid in the liquid source will recede over time, and the patient may move, resulting in variations in the pressure differential that determines the flow rate of the liquid. Additionally, tubing and/or other components of the intravenous delivery system may become pinched, blocked, or otherwise occluded, resulting in unexpected changes in the flow rate of the liquid.
Currently, clinicians often measure the flow rate of the liquid by counting the drops entering the drip chamber over a set period of time. The clinician must then calculate the resulting flow rate and compare it to the desired flow rate to determine the necessary flow rate adjustment. This flow rate adjustment may then be made by manually adjusting a device such as a clamp on the tubing. The clinician may then count the drops entering the drip chamber again to determine whether the desired flow rate has been achieved. This procedure is time-consuming for the clinician, and subject to human error.
Accordingly, a less time-consuming and more reliable method is needed for controlling the flow rate of liquid delivered via an intravenous delivery system. Further, in order to reduce the cost of medical care delivery, there exists a need for such methods to be simple and cost-effective, and preferably to avoid the necessity for complicated equipment.